Plasmids in BL21 codon plus

Michael L. Sullivan mlsulliv at
Tue Mar 27 10:04:47 EST 2001

Check the information at  I believe their literature
tells what bands you can expect from BL21 RIL.  Also, you could do plasmid
prep of the codon plus cells not transformed with your plasmid and use that
as a control to know which bands are derived from the RIL plasmid.


>Hi, I assume that the extra tRNA carried by
>the codon plus Bl21 cells (Promega) are carried on
>a plasmid under cam selection.
>Well, when I do a miniprep of these cells transformed
>with my plasmid I see extra bands both in digested and
>non digested DNA; I need to know if these extra bands
>come from the "endogenous" plasmid. Anyone has got
>the sequence (or restriction map) of the plasmid carring the extra
>tRNAs in the BL21(DE3)codon-plus RIL cells?
>In case of affermative answer can U mail me it?
>Bye, Gianluca
>Gianluca Molla PhD
>Università dell'Insubria (ITALY)
>gianluca.molla at


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